1. Field of the Invention
The present invention relates to inflatable protective cushions of the kind useful in automotive vehicles, and more particularly to protective cushions of the kind which are substantially instantaneously inflatable and positonable to protect passengers from injuries in case the vehicles are involved in a front-end collision.
Inflatable protective cushions, conventionally known as air bags, have been proposed for installation in passenger vehicles as devices to protect passengers from injuries which may result from a collision with an impediment or an approaching vehicle.
In their folded-down inoperative position the cushions are typically compactly folded and stored in containers in or near the dashboard or in the back rest of a front seat if the cushions are to protect passengers occupying rear seats. If the vehicle is involved in a front-end collision a source of pressurized gas is activated abruptly or at least substantially instantly to inflate the cushion and to move it into a protective position between the passenger and structure of the vehicle likely to cause injury to the passenger.
To be effective an air bag must not only be convertible from its compact folded condition to its inflated large volume condition in an instant, but it should also, to be an attractive feature of an automobile, be of as small a volume as possible when in its folded-down condition so that its storage container may be dimensioned correspondingly small to be inconspicuous.
2. Description of the Prior Art.
West German Patent Specification DE-OS 27 22 551 discloses an inflatable protective cushion of substantially drum-like configuration. However, because of its necessarily circular end surfaces it is very difficult to fold such a cushion into a regular and uniform shape. Moreover, the circular end surfaces of such a cushion result in excessive waste of material during its manufacture.
West German Patent Specification DE-OS 25 36 933 discloses substantially circular cushions which when inflated are of relatively small volume and which may be foldable with relative ease; but again, the cutting of their blanks results in much wasted material.
West German Patent Specifications DE-OSn 25 28 636 and 25 29 602, for instance, disclose air bags the shapes of which, when inflated, conform more or less to the body of a passenger. These air bags are made from substantially rectangular blanks. Unfortunately, they require too many seams which makes their manufacture unduly complicated and correspondingly dear. Also, in their folded-down condition these air bags occupy unduly large spaces.
Somewhat similar air bags are taught by west German Patent Specifications DE-OSn 23 22 629 (U.S. Pat. No. 3,810,654) and 22 24 827. When folded-down, these are of substantially rectangular configuration with substantially congruent impact surfaces; but because of seams which determine their configuration in the inflated condition they cannot be folded down into a truly compact shape.
3. Summary of the Invention and Objects
It is an object of the invention to provide an inflatable protective cushion which may be made with no or substantially no waste.
It is a further object of the invention to provide a protective cushion which requires few seams only so that it may be manufactured in a cost-effective manner.
It is also object of the invention to provide a protective cushion which may be folded down easily and uniformly into a very small volume.
It is also an object of the invention to provide a protective inflatable cushion the seams of which do not adversely influence the shape of the cushion in its inflated condition.
Moreover, an object of the invention resides in the provision of an airbag which when inflated provides for a large volume in its effective or active direction, i.e. in the direction in which impact forces act.
Other objects will in part be obvious and will in part appear hereinafter.